Sheet feeding device

Abstract

A sheet feeding device includes a feeding unit that feeds a sheet; a rolling member that rolls by having contact with the sheet being fed by the feeding unit; a supporting member that moves along with a behavior of the sheet with supporting the rolling member so that the rolling member rolls in a feeding direction of the sheet at a predetermined position on the sheet; an acceleration measuring unit that measures accelerations acting on the supporting member in three directions; and a detecting unit that detects a feed error of the sheet based on the accelerations measured by the acceleration measuring unit.

1 . A sheet feeding device comprising:
 a feeding unit that feeds a sheet;   a rolling member that rolls by having contact with the sheet being fed by the feeding unit;   a supporting member that moves along with a behavior of the sheet with supporting the rolling member so that the rolling member rolls in a feeding direction of the sheet at a predetermined position on the sheet;   an acceleration measuring unit that measures accelerations acting on the supporting member in three directions; and   a detecting unit that detects a feed error of the sheet based on the accelerations measured by the acceleration measuring unit.   
     
     
         2 . The sheet feeding device according to  claim 1 , wherein
 the acceleration measuring unit measures accelerations in the feeding direction, a width direction horizontally-perpendicular to the feeding direction, and a height direction perpendicular to both the feeding direction and the width direction, and   the supporting member moves in the height direction and rotates around an axis along the height direction along with the behavior of the sheet.   
     
     
         3 . The sheet feeding device according to  claim 2 , wherein the detecting unit detects a skew of the sheet as a feed error of the sheet when an increase or decrease of any of the accelerations in the feeding direction and the width direction is continued for a predetermined time period. 
     
     
         4 . The sheet feeding device according to  claim 2 , wherein the detecting unit detects a jam of the sheet as a feed error of the sheet when an increase or decrease of the acceleration in the height direction is continued for a predetermined time period. 
     
     
         5 . The sheet feeding device according to  claim 2 , further comprising
 a vibration applying unit that applies a periodical vibration in the height direction to the acceleration measuring unit;   a waveform generating unit that generates an acceleration waveform of the acceleration in the height direction based on a result of measurement by the acceleration measuring unit;   a storing unit that stores therein a reference acceleration waveform as a reference of the acceleration waveform in the height direction depending on a feeding speed of the sheet fed by the feeding unit; and   a comparing unit that compares the acceleration waveform generated by the waveform generating unit with the reference acceleration waveform, wherein   the detecting unit detects a feed error of the sheet based on a result of comparison by the comparing unit.   
     
     
         6 . The sheet feeding device according to  claim 1 , wherein the rolling member has a cylindrical shape, and a rotating shaft of the rolling member is arranged along the width direction. 
     
     
         7 . The sheet feeding device according to  claim 1 , further comprising an arm member having a base end portion and a leading end portion, wherein
 the base end portion of the arm member is fixed to the supporting member and the acceleration measuring unit is provided on the leading end portion of the arm member.   
     
     
         8 . The sheet feeding device according to  claim 1 , further comprising a stacking member on which a plurality of sheets are stacked, wherein
 the feeding unit includes a separating unit that separates the sheets stacked on the stacking member one by one, and   the rolling member is arranged on an upstream side of the separating unit in the feeding direction.   
     
     
         9 . The sheet feeding device according to  claim 1 , further comprising a feeding stop unit that stops a feeding of the sheet by the feeding unit depending on a result of detection by the detecting unit. 
     
     
         10 . The sheet feeding device according to  claim 1 , wherein the rolling member has point contact with the sheet at a plurality of points located along a width direction horizontally-perpendicular to the feeding direction. 
     
     
         11 . The sheet feeding device according to  claim 1 , wherein the rolling member has line contact with the sheet on a line along a width direction horizontally-perpendicular to the feeding direction.